But her fellow qualifier Bencic secured her first victory in the main draw of a grand slam by beating Kimiko Date-Krumm 6-4 4-6 6-3.

It was a real generational battle, with Date-Krumm an astonishing 27 years older than her opponent.

Swiss Bencic is coached by Melanie Molitor, the mother of Martina Hingis, and Hingis was in the stands to see the teenager triumph.

Bencic said: "She gave me some advice and I tried to do it. I was a little bit nervous in the beginning but then I just tried to keep the ball in the court. It was special."

Konjuh won the junior title at Melbourne Park last year and, despite the scoreline, Li backed her opponent to rise to the top.

Li tried to find clips of Konjuh on YouTube so she would know what to expect, and she said: "She has a huge serve and very good baseline play.

"I was feeling that if she had more experience, I think she'll be a very good player."

It was a convincing start for Li, who lost to Victoria Azarenka in the final last year and next meets Bencic.

Seventh seed Sara Errani was the first major casualty of the tournament, the Italian going down 6-3 6-2 to Germany's Julia Goerges.

In truth, it was not a huge surprise. Errani also lost in the first round last year and has not been in good form so far this season.

Home hope Sam Stosur fought back from 1-4 down in the second set to defeat Klara Zakopalova for the third time in the first round in Melbourne.

The 6-3 6-4 victory was nevertheless a notable result for the Australian 17th seed, who lost to Czech Zakopalova in Hobart on Friday.

Ana Ivanovic also made it through, the 14th seed defeating Dutchwoman Kiki Bertens, who had her blood pressure taken on court after struggling with the heat, 6-4 6-4.

There was no happy return to grand slam tennis, though, for two-time grand slam finalist Vera Zvonareva, who was beaten 6-2 6-2 by Australian wild card Casey Dellacqua.

The Russian, who made the finals at Wimbledon and the US Open in 2010, played her first grand-slam match since Wimbledon in 2012 following 17 months out through illness and shoulder surgery.

There were also wins for teenagers Eugenie Bouchard, Madison Keys and Annika Beck, along with seeds Angelique Kerber, Daniela Hantuchova and Kirsten Flipkens.

Errani's doubles partner, 12th seed Roberta Vinci, went the same way, losing 6-4 6-3 to Zheng Jie, but the big shock of the day was former Wimbledon champion Petra Kvitova's defeat by Thai Luksika Kumkhum.

Twenty-year-old Kumkhum has been steadily climbing the rankings, reaching 88, but there was nothing in her results to indicate she could pull off an upset of the nature of her 6-2 1-6 6-4 victory.

Sixth seed Kvitova has been plagued by inconsistency since her Wimbledon-winning season of 2011 and made 40 unforced errors.

The Czech could offer little explanation, saying: "I really want to know what happened out there. Unfortunately I didn't play well. I didn't play my game that I really tried all off season to work on.

"It was a great off season. I was really excited to be here, feeling good. But I think that probably I wanted it too much, and then everything just fell down."

German 15th seed Sabine Lisicki, who is being coached here by Hingis, was a 6-2 6-1 winner over Mirjana Lucic-Baroni.